Japanese Laid-open Patent Publication No. 2003-312329A discloses a vehicle seat reclining device that includes a portion affixed to the side of a vehicle body. The vehicle seat reclining device cooperates with a locking device, which is affixed to the tiltable backrest of a vehicle seat, so as to permit the backrest to be selectively locked in a stepwise manner in a series of tilted positions.
The known vehicle seat reclining device includes a rail, a slider, and a latch mechanism. The rail extends along a central axial line. The rail is affixed to the side of the vehicle body so as to be tangential to a path traced in space by the locking device as the backrest tilts. The slider is slidably attached to the rail, and includes a striker configured to engage with the locking device. The latch mechanism is provided between the rail and the slider, and prevents or allows the slider to slide along the rail.
More specifically, the latch mechanism includes a plurality of latch holes formed in the rail and aligned along the central axial line, a slider hole that penetrates through the slider so as to face and be alignable with each of the respective latch holes, a support portion provided on the slider, and a movable portion displaceably supported by the support portion. The movable portion includes a latch projection that is engageable with each of the respective latch holes by passing through the slider hole. A clearance in the direction of the central axial line is provided between the latch projection and each side of the slider hole. Due to this clearance, the latch projection can easily slide within the slider hole, so that the latch projection can smoothly engage in each of the respective latch holes.
In the known vehicle seat reclining device having the above-described configuration, the latch mechanism can be operated so as to disengage the latch projection from the respective latch holes, thereby enabling a change of the tilted position of the backrest by sliding the slider along the rail. The backrest can then be fixed at a desired tilted position by engaging the latch projection with the corresponding latch hole.